Asymptomatic infants who are destined to die from metachromatic leukodystrophy (MLD), can be identified by urine positive for sulfatides. When detected early in life, bone marrow transplantation can provide, according to initial data, an effective, perhaps curative, treatment. Elevated urine sulfatides of MLD patients are characteristic of this disease. Detection of sulfatides can be accomplished by using urine-soaked filter paper, a collection method used for mass screening of other diseases. Sulfatides from filter papers can be extracted and quantified by electrospray ionization mass spectrometry. This Phase II project will: 1. perform semi-automated urinary sulfatide and sphingomyelin analysis of 10,000 previously collected urine-soaked filter papers by electrospray ionization mass spectrometry to a) establish and validate a robust procedure for metachromatic leukodystrophy screening and b) estimate false positive frequency, and to 2. identify MLD urines and the occurrence of possible false negative frequency, and to demonstrate the commercial applicability of the method of MLD screening by performing semi-automated urinary sulfatide and sphingomyelin analysis of - 100,000 previously collected urine-soaked filter paper, 3. improve on method efficiency by testing new advancements in technology and design. PROPOSED COMMERCIAL APPLICATION: A method of screening 6-month-old infants for metachromatic leukodystrophy will be developed. Subsequent to continued proof of validity of the screening method and positive reinforcement from bone marrow transplantation, the number of infants screened will potentially be several million each year. The commercial application of this research will then be realized from either licensing, joint venture, or testing with cost plus profit.